Abstract: In this study,the small-leaf kudingcha polyphenol extract was studied,and its ability to remove DPPH (1,1-diphenyl-2-picryhydrazl) free radicals,ABTS (2,2-azino-bis (3-ethylbenzothiazoline 6-sulfonic acid)) free radicals and hydroxyl radicals were measured in vitro. A mouse model of gastric injury induced by hydrochloric acid/ethanol was established using 60% alcohol and 40% 150 mmol/L hydrochloric acid mixture as inducers,and the activities of related enzymes in mouse serum and gastric tissues,the changes of histopathological sections were detected. The mRNA expression of endothelial nitric oxide synthase (eNOS),neural nitric oxide synthase (nNOS) and cyclooxygenase-2 (cox-2) was determined,and the preventive effects of small-leaf kudingcha polyphenol extract on alcoholic gastric injury in mice were comprehensively evaluated. Small-leaf kudingcha polyphenol extract had strong reducing ability and could effectively remove DPPH (1,1-diphenyl-2-picryhydrazl) free radicals and ABTS (2,2-azino-bis (3-ethylbenzothiazoline-) 6-sulfonic acid)) free radicals and hydroxyl radicals,with the increase of concentration,the scavenging ability was gradually enhanced. The results of animal experiments showed that the small-leaf kudingcha polyphenol extract could reduce the degree of gastric injury in mice,increase the gastric injuryinhibition rate,reduce the secretion of gastric juice and increase the pH value of gastric juice. Compared with the model group,the small-leaf kudingcha polyphenol extract significantly increased superoxide dismutase (SOD) activity and glutathione (GSH) content,decreased malondialdehyde (MDA) production (p<0.05),and relieved gastric histopathology,significantly up-regulate Cu/Zn-superoxide dismutase (Cu/Zn-SOD),Mn-superoxide dismutase (Mn-SOD),catalase (CAT),endothelial nitric oxide synthase (eNOS),neuronal nitric oxide synthase (nNOS) mRNA expressions (p<0.05),decreased inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions,and the effect of high concentration (200 mg/kg) of the polyphenol extract of the tea was more obvious than that of low concentration (100 mg/kg). It can be seen that small-leaf kudingcha polyphenol extract (SKCPE) can effectively alleviate the degree of gastric injury induced by hydrochloric acid/ethanol in mice,SKCPE is a kind of active component with improving gastric injury,therefore it has a good application prospect.